This invention relates to a high water content dentifrice composition and, more particularly, to such a dentifrice composition that has a water content of greater than 50% by weight and a viscosity of greater than 200,000 centipoise (cP). The invention also relates to a method of making such a dentifrice composition.
Dentifrice compositions generally contain combinations of an abrasive material with one or typically several of a thickener system, a humectant system, a flavoring agent and a foaming agent. Other ingredients commonly found in dentifrice compositions such as toothpaste formulations include detergents or surfactants, coloring or whitening agents, preservatives, antibacterial agents and fluorides.
The use of silica as the abrasive component in toothpaste formulations dramatically changed dentifrice technology over twenty years ago when fluoride became established as an anticaries active ingredient for prevention of tooth decay. Unlike calcium carbonate, dental-grade silica proved to be compatible with most fluoride sources. Its predominant use in dentifrice in industrialized countries has contributed to a major decline in caries and tooth decay among school-aged children. The World Health Organization has as a top priority elimination of dental caries. The Oral Health Division of Noncommunicable Diseases, World Health Organization, published in 1998 a report entitled xe2x80x9cSchool-based Primary Preventive Programme for Childrenxe2x80x9d. One objective of the project described in this report is to encourage companies to produce xe2x80x9can affordable fluoride containing toothpaste.xe2x80x9d
While the beneficial impact of the use of a fluoride-containing dentifrice on oral hygiene and dental health is well documented, such compositions are relatively expensive for many consumers and, therefore are not widely affordable in many developing countries. The cost of a given dentifrice formulation is often dictated by the amount of water that can be incorporated therein. Given the economics involved, the dentifrice formulation ideally would contain as high a water fraction as possible without sacrificing the needed performance and aesthetics. Nonetheless, the notion of significantly increasing the water content per se of a dentifrice raises concerns of undermining, for example, the stability and uniformity of the dentifrice formulation, its ability to retain its body and shape without experiencing inordinate sagging when extruded upon toothbrush bristles in order to sufficiently sit on the bristles, or the tendency of the formulation not to readily seep out of the dispenser tube when opened. In practice, merely increasing the water content in conventional dentifrice formulations, all other things kept equal, has been observed to have a deleterious impact on stability, mouthfeel and rheological properties.
In any event, liquid dentifrice compositions have been marketed, particularly but not exclusively in Europe, for many years. These compositions could contain relatively high amounts of water, but they have lower viscosity and thinner mouthfeel than typical toothpaste formulations to which many other consumers have grown accustomed and prefer from aesthetical and performance standpoints. Many consumers will not accept a runny toothpaste. On the other hand, although a toothpaste needs body, it cannot be lumpy or overly sticky either. Examples of measured viscosity values for several sampled commercial liquid dentifrice compositions are provided in Table A below.
In view of the above, it can be appreciated that a challenge and need has existed in the dentifrice field for development of a liquid dentifrice that can sustain increased water content yet without sacrificing the desired performance and aesthetics.
The present invention overcomes the deficiencies of the prior art and meets the challenges discussed above. This invention provides a high water content dentifrice composition that has acceptable stability, mouthfeel and Theological properties. The inventive dentifrice composition also is relatively inexpensive to manufacture, which can translate into a more affordable product for consumers. To achieve these and other advantages, benefits, and enhancements, a high water content dentifrice composition having a viscosity greater than about 200,000 centipoise (cP) is provided according to this invention comprising a water content greater than about 50% by weight, abrasive material, binder, and polyol humectant.
In accordance with one embodiment of the present invention, the high water content dentifrice composition having a viscosity greater than 200,000 cP and including water in an amount of greater than about 50% by weight is formulated as an admixture therewith of abrasive material in an amount of about 8% to about 18% by weight, silica thickener in an amount of about 8% to about 15% by weight, binder in an amount of about 0.5% to about 1.5% by weight, and polyol humectant in an amount of about 1% to about 20% by weight.
In order to render the inventive dentifrice compositions xe2x80x9ctherapeuticxe2x80x9d in nature, the dentifrice compositions of the present invention typically also will contain a water soluble fluorine-containing compound and/or other active compound(s) insofar as having a beneficial effect on the care and hygiene of the oral cavity by protecting the teeth against decay, reducing the acid solubility of the tooth enamel, reducing plaque, and/or reducing oral bacteria, among other things. For instance, fluorine-containing compounds providing one or more of these properties can be included in an effective, non-toxic amount in the formulation, which generally can range from about 0.01 to about 1% by weight of the overall formulation.
Other objects, features and advantages will be readily apparent from the following detailed description of preferred embodiments thereof.